Question

A substance decay 22% each day after seven days there are 9 mg of the substance remaining how many milligrams were there initially

Answer 1

To find the initial amount, we can set up an equation using exponential decay. After simplification, we find that the initial amount of the substance is approximately 23.86 mg.

Step-by-step explanation:

To find the initial amount of the substance, we can set up an equation using exponential decay. We know that the substance decays by 22% each day, so after 7 days, there are 9 mg remaining. Let x represent the initial amount of the substance.

x * (1 - 0.22)^7 = 9

Simplifying the equation, we have x * 0.377 = 9. Dividing both sides by 0.377, we find that the initial amount of the substance is approximately 23.86 mg.